strmode() function declaration buglet fixed

Was converting files to proper ANSI C function declarations and a user tripped over the fact that old 4.4 BSD's function prototype of strmode() had int as a parameter, whereas it has been mode_t for a long, long time (read 1994 at least).

This broke buildworld of course.

Also asked Dima Dorfman to fix this for FreeBSD (broken in 4.x, 5.x, and 6.x).

NetBSD is fixed (as was to be expected to be honest).

And OpenBSD made the parameter int everywhere with a XXX comment in the strmode.c file that it should be mode_t actually. Weird.